Capacity control valve

ABSTRACT

A capacity control valve ( 1 ) includes a valve main body ( 10 ) having a first communication passage ( 11 ), a second communication passage ( 12 ), a third communication passage ( 13 ), and a main valve seat ( 15   a ), a pressure-sensitive body ( 24 ), a valve element ( 20 ) having an intermediate communication passage ( 29 ), a main valve portion ( 21   c ), and a restrictor portion ( 25 ), and a solenoid ( 30 ) that drives a rod ( 36 ). The rod ( 36 ) is relatively moved with respect to the valve element ( 20 ) so as to control an opening degree of the restrictor portion ( 25 ). The capacity control valve is capable of efficiently discharging a liquid coolant irrespective of pressure of a suction chamber and improving control stability.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is the U.S. National Phase under 35 U.S.C. § 371 ofInternational Application PCT/JP2019/001570, filed Jan. 21, 2019, whichclaims priority to Japanese Patent Application No. JP2018-008486, filedJan. 22, 2018. The International Application was published under PCTArticle 21(2) in a language other than English.

TECHNICAL FIELD

The present invention relates to a capacity control valve used forcontrolling a flow rate or pressure of a variable capacity compressor.

BACKGROUND ART

As the variable capacity compressor, for example, a swash plate typevariable capacity compressor used in an air conditioning system of anautomobile, etc. includes a rotation shaft to be driven and rotated byrotation force of an engine, a swash plate coupled to the rotation shaftso that a tilting angle is variable, and compressing pistons coupled tothe swash plate, etc., and is to change strokes of the pistons andcontrol a discharge amount of a coolant by changing the tilting angle ofthe swash plate.

This tilting angle of the swash plate can be continuously changed byappropriately controlling pressure in a control chamber by using acapacity control valve to be driven and opened/closed by electromagneticforce while utilizing suction pressure of a suction chamber to which thecoolant is sucked in, discharge pressure of a discharge chamber fromwhich the coolant pressurized by the pistons is discharged, and controlchamber pressure of the control chamber (crank chamber) in which theswash plate is housed, and by adjusting a balance state of pressureacting on both surfaces of the pistons.

FIG. 5 shows an example of such a capacity control valve. A capacitycontrol valve 160 includes a valve portion 170 having a second valvechamber 182 which communicates with the discharge chamber of thecompressor via a second communication passage 173, a first valve chamber183 which communicates with the suction chamber via a firstcommunication passage 171, and a third valve chamber 184 whichcommunicates with the control chamber via a third communication passage174, a pressure-sensitive body 178 arranged in the third valve chamber,the pressure-sensitive body to be extended and contracted by peripheralpressure, the pressure-sensitive body having a valve seat body 180provided in a free end in the extending and contracting direction, avalve element 181 having a second valve portion 176 which opens andcloses a valve hole 177 providing communication between the second valvechamber 182 and the third valve chamber 184, a first valve portion 175which opens and closes the first communication passage 171 and adistribution groove 172, and a third valve portion 179 which opens andcloses the third valve chamber 184 and the distribution groove 172 byengagement with and disengagement from the valve seat body 180 in thethird valve chamber 184, a solenoid portion 190 which applieselectromagnetic drive force to the valve element 181, etc.

In this capacity control valve 160, without providing a clutch mechanismin the variable capacity compressor, in a case where the need forchanging the control chamber pressure arises, the pressure (controlchamber pressure) Pc in the control chamber and the suction pressure Ps(suction pressure) can be controlled by providing communication betweenthe discharge chamber and the control chamber (hereinafter, referred toas the “conventional art”. See Patent Document 1, for example).

CITATION LIST Patent Documents

Patent Document 1: JP 5167121 P

SUMMARY OF THE INVENTION Problem to be Solved by the Invention

In the conventional art, in a case where the swash plate type variablecapacity compressor is stopped for a long time, a liquid coolant (madeby cooling and liquefying a coolant during abandonment) is accumulatedin the control chamber (crank chamber). Thus, even when the compressoris started up in this state, it is not possible to ensure a dischargeamount as it is set. Therefore, in order to perform desired capacitycontrol immediately after start-up, there is a need for discharging theliquid coolant of the control chamber (crank chamber) as soon aspossible.

As shown in FIG. 6, the conventional capacity control valve 160 includesa function of discharging the liquid coolant in order to discharge theliquid coolant of the control chamber (crank chamber) as soon aspossible at the time of start-up. That is, in a case where the variablecapacity compressor is stopped and abandoned for a long time and thenstarted up, the high-pressure liquid coolant accumulated in the controlchamber (crank chamber) flows into the third valve chamber 184 from thethird communication passage 174. Then, the pressure-sensitive body 178is contracted, a part between the third valve portion 179 and the valveseat body 180 is opened, and from the third valve chamber 184 throughthe auxiliary communication passage 185, the communication passage 186,and the distribution groove 172, the liquid coolant is discharged to thedischarge chamber from the control chamber (crank chamber) via thesuction chamber and rapidly gasified, so that it is possible to make acooling operation state for a short time.

However, in the above conventional art, at an initial stage of a liquidcoolant discharging process, pressure of the control chamber is high andhence an opening degree of the third valve portion 179 is large. Thus,it is possible to efficiently discharge the liquid coolant. However, asdischarge of the liquid coolant progresses and the pressure of thecontrol chamber is lowered, the opening degree of the third valveportion 179 is decreased. Thus, there is a problem that it takes time todischarge the liquid coolant.

The capacity control valve 160 sets an opening degree of the secondvalve portion 176 to an opening degree determined in advance andcontrols so that the pressure and the discharge amount of the suctionchamber of the variable capacity compressor have set values. However,the pressure of the control chamber (crank chamber) of the variablecapacity compressor is gradually increased by a blow-by gas flowingthrough a tiny clearance between a piston and a cylinder bore. Thus, thepressure of the control chamber is not stabilized and there is sometimesa case where control stability of the capacity control valve 160 isdeteriorated.

The present invention is achieved to solve the problems of the aboveconventional art, and an object of the present invention is to provide acapacity control valve capable of, in the capacity control valve thatcontrols a flow rate or pressure of a variable capacity compressor inaccordance with a valve opening degree of a valve portion, efficientlydischarging a liquid coolant irrespective of pressure of a suctionchamber, shifting to a cooling operation for a short time, and improvingcontrol stability.

Means for Solving Problem

In order to solve the foregoing problems, a capacity control valveaccording to a first aspect of the present invention is a capacitycontrol valve that controls a flow rate or pressure of a variablecapacity compressor in accordance with a valve opening degree of a valveportion, the capacity control valve being characterized by including avalve main body having a first communication passage through which afluid of first pressure passes, a second communication passage arrangedadjacent to the first communication passage, the second communicationpassage through which a fluid of second pressure passes, a thirdcommunication passage through which a fluid of third pressure passes,and a main valve seat arranged in a valve hole which providescommunication between the second communication passage and the thirdcommunication passage, a pressure-sensitive body arranged in the valvemain body on the third communication passage side, thepressure-sensitive body to be extended and contracted in accordance withperipheral pressure, a solenoid that drives a rod having a pressingportion that presses the pressure-sensitive body, a valve element havingan intermediate communication passage providing communication betweenthe first communication passage and the third communication passage, amain valve portion to be separated from and connected to the main valveseat so as to open and close the valve hole, and a restrictor portionopposing the pressing portion, the restrictor portion that narrows downthe intermediate communication passage, and a first biasing member thatbiases the valve element in the valve closing direction of the mainvalve portion, characterized in that the rod is relatively moved withrespect to the valve element so as to control an opening degree of therestrictor portion.

According to the first aspect, in coolant discharge, the rod maintainsthe opening degree of the restrictor portion in a fully opened state andit is possible to efficiently discharge a liquid coolant from the thirdcommunication passage to the first communication passage through theintermediate communication passage irrespective of pressure of a suctionchamber.

The capacity control valve according to a second aspect of the presentinvention is characterized in that the restrictor portion has acommunication passage that separates the pressing portion from the valveelement and communicates with the intermediate communication passage.

According to the second aspect, a spacer separates the pressing portionfrom the valve element and by a communication passage of the spacer, thecoolant is always discharged from the third communication passage to thefirst communication passage. Thus, it is possible to prevent pressure ofa crank chamber from being increased by a blow-by gas so as to stabilizethe pressure of the crank chamber. Thus, it is possible to improvestability of the capacity control valve.

The capacity control valve according to a third aspect of the presentinvention is characterized in that an opening area of the communicationpassage is smaller than an area of a clearance between the valve elementand the pressing portion.

According to the third aspect, the communication passage serves as abottleneck in the intermediate communication passage. Thus, by adjustingonly the opening area of the communication passage, it is possible toadjust an amount of the coolant flowing from the third communicationpassage to the first communication passage.

The capacity control valve according to a fourth aspect of the presentinvention is characterized in that the first biasing member is arrangedbetween the rod and the valve element.

According to the fourth aspect, it is possible to drive the valveelement by the rod via the first biasing member.

The capacity control valve according to a fifth aspect of the presentinvention is characterized in that the solenoid further includes aplunger connected to the rod, a core arranged between the plunger andthe valve main body, an electromagnetic coil, and a second biasingmember arranged between the plunger and the core.

According to the fifth aspect, by the second biasing member arrangedbetween the plunger and the core, the valve element is reliably biasedin the valve opening direction of the main valve portion. Thus, it ispossible to open the main valve portion when the solenoid is turned off.

The capacity control valve according to a sixth aspect of the presentinvention is characterized in that the first pressure is suctionpressure of the variable capacity compressor, the second pressure isdischarge pressure of the variable capacity compressor, and the thirdpressure is pressure of a crank chamber of the variable capacitycompressor. The capacity control valve according to a seventh aspect ofthe present invention is characterized in that the first pressure ispressure of a crank chamber of the variable capacity compressor, thesecond pressure is discharge pressure of the variable capacitycompressor, and the third pressure is suction pressure of the variablecapacity compressor.

According to the sixth or seventh aspect, it is possible to respond tovarious variable capacity compressors.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a front sectional view of a capacity control valve accordingto the present invention.

FIG. 2 is an enlarged view of part of a valve main body, a valveelement, and a solenoid of FIG. 1 showing the capacity control valve atthe time of turning off the solenoid.

FIG. 3 is an enlarged view of part of the valve main body, the valveelement, and the solenoid of FIG. 1 showing a control state of thecapacity control valve.

FIG. 4 is an enlarged view of part of the valve main body, the valveelement, and the solenoid of FIG. 1 showing a state of the capacitycontrol valve at the time of liquid coolant discharge.

FIG. 5 is a front sectional view showing a conventional capacity controlvalve.

FIG. 6 shows a state of the conventional capacity control valve at thetime of liquid coolant discharge.

DESCRIPTION OF EMBODIMENTS

Hereinafter, with reference to the drawings, a mode for carrying out thepresent invention will be described illustratively based on anembodiment. However, the dimensions, materials, shapes, relativepositions, etc. of constituent parts described in this embodiment arenot limited only to themselves unless otherwise described particularlyexplicitly.

With reference to FIGS. 1 to 4, a capacity control valve according tothe present invention will be described. In FIG. 1, the reference sign 1denotes a capacity control valve. The capacity control valve 1 is mainlyformed by a valve main body 10, a valve element 20, a pressure-sensitivebody 24, and a solenoid 30.

Hereinafter, with reference to FIGS. 1 and 2, respective constituentelements of the capacity control valve 1 will be described. The valvemain body 10 is made of metal such as brass, iron, aluminum, stainless,or synthetic resin, etc. The valve main body 10 is a cylindrical hollowmember having a through hole which passes through in the axialdirection. In sections of the through hole, a first valve chamber 14, asecond valve chamber 15 adjacent to the first valve chamber 14, and athird valve chamber 16 adjacent to the second valve chamber 15 arecontinuously arranged.

A second communication passage 12 is continuously provided in the secondvalve chamber 15. This second communication passage 12 communicates withthe inside of a discharge chamber (not shown) of a variable capacitycompressor so that a fluid of discharge pressure Pd (second pressureaccording to the present invention) can flow in from the second valvechamber 15 to the third valve chamber 16 by opening and closing thecapacity control valve 1.

A third communication passage 13 is continuously provided in the thirdvalve chamber 16. The third communication passage 13 communicates with acontrol chamber (not shown) of the variable capacity compressor so thatthe fluid of discharge pressure Pd flowing in from the second valvechamber 15 to the third valve chamber 16 by opening and closing thecapacity control valve 1 flows out to the control chamber (crankchamber) of the variable capacity compressor and a fluid of controlchamber pressure Pc (third pressure according to the present invention)flowing into the third valve chamber 16 flows out to a suction chamberof the variable capacity compressor via an intermediate communicationpassage 29 to be described later and through the first valve chamber 14.

Further, a first communication passage 11 is continuously provided inthe first valve chamber 14. This first communication passage 11 leads afluid of suction pressure Ps (first pressure according to the presentinvention) from the suction chamber of the variable capacity compressorto the pressure-sensitive body 24 via the intermediate communicationpassage 29 to be described later, and controls the suction pressure ofthe compressor to a set value.

Between the first valve chamber 14 and the second valve chamber 15, ahole portion 18 having a diameter smaller than a diameter of any ofthese chambers is continuously formed. This hole portion 18 slides witha labyrinth 21 f to be described later and forms a seal portion thatseals a part between the first valve chamber 14 and the second valvechamber 15. Between the second valve chamber 15 and the third valvechamber 16, a valve hole 17 having a diameter smaller than a diameter ofany of these chambers is continuously provided. A main valve seat 15 ais formed around the valve hole 17 on the second valve chamber 15 side.This main valve seat 15 a is separated from and connected to a mainvalve portion 21 c to be described later so as to control opening andclosing of a Pd-Pc flow passage providing communication between thesecond communication passage 12 and the third communication passage 13.

The pressure-sensitive body 24 is arranged in the third valve chamber16. One end portion of a metal bellows 24 a of this pressure-sensitivebody 24 is combined to a partition adjusting portion 24 f in a sealedstate. This bellows 24 a is made of phosphor bronze, stainless, etc. anda spring constant of the bellows is designed to be a predeterminedvalue. An internal space of the pressure-sensitive body 24 is vacuum orthe air exists in the internal space. Pressure acts on a valid pressurereceiving area of the bellows 24 a of this pressure-sensitive body 24 sothat the pressure-sensitive body 24 is extended and contracted. A flangeportion 24 d is arranged on the free end portion side of thepressure-sensitive body 24. By directly pressing this flange portion 24d by a pressing portion 26 of a rod 36 to be described later, thepressure-sensitive body 24 is extended and contracted. That is, asdescribed later, the pressure-sensitive body 24 is extended andcontracted in accordance with the suction pressure Ps led to thepressure-sensitive body 24 via the intermediate communication passage29, and also extended and contracted by pressing force of the rod 36.

The partition adjusting portion 24 f of the pressure-sensitive body 24is sealed, fitted, and fixed so as to close the third valve chamber 16of the valve main body 10. By screwing the partition adjusting portion24 f and fixing by a locking screw (not shown), it is possible to adjustaxial movement of spring force of a compression spring arranged inparallel in the bellows 24 a or the bellows 24 a.

For example, two to six parts of each of the first communication passage11, the second communication passage 12, and the third communicationpassage 13 pass through a peripheral surface of the valve main body 10at equal intervals. Further, attachment grooves for O rings are providedat three points while being separated in the axial direction on an outerperipheral surface of the valve main body 10. O rings 47, 48, 49 thatseal a part between the valve main body 10 and an installment hole of acasing (not shown) fitted to the valve main body 10 are attached to theattachment grooves. Flow passages of the first communication passage 11,the second communication passage 12, and the third communication passage13 are formed as independent flow passages.

Next, the valve element 20 will be described. The valve element 20 ismainly formed by a main valve element 21 which is a cylindrical hollowmember, and an adapter 23. First, the main valve element 21 will bedescribed. The main valve element 21 is a cylindrical hollow member, andthe labyrinth 21 f is formed in a substantially center portion in theaxial direction of an outer peripheral portion of the main valveelement. The main valve element 21 is inserted into the valve main body10, and the labyrinth 21 f slides on the hole portion 18 between thefirst valve chamber 14 side and the second valve chamber 15 side so asto form a seal portion that seals the first valve chamber 14 and thesecond valve chamber 15. Thereby, the first valve chamber 14communicating with the first communication passage 11 and the secondvalve chamber 15 communicating with the second communication passage 12are formed as independent valve chambers.

The main valve element 21 is arranged on the first communication passage11 side and on the second communication passage 12 side across thelabyrinth 21 f. The main valve portion 21 c is formed in an end portionof the main valve element 21 arranged on the second communicationpassage 12 side. The main valve portion 21 c is separated from andconnected to the main valve seat 15 a so as to control opening andclosing of the valve hole 17 providing communication between the secondcommunication passage 12 and the third communication passage 13. Themain valve portion 21 c and the main valve seat 15 a form a main valve27 b. A situation where the main valve portion 21 c and the main valveseat 15 a are brought from a contact state into a separate state will beindicated as the main valve 27 b is opened or the main valve portion 21c is opened. A situation where the main valve portion 21 c and the mainvalve seat 15 a are brought from a separate state into a contact statewill be indicated as the main valve 27 b is closed or the main valveportion 21 c is closed. A shut-off valve portion 21 a is formed in anend portion of the main valve element 21 arranged in the first valvechamber 14. When the solenoid 30 to be described later is turned off,the shut-off valve portion 21 a is brought into contact with an endportion 32 c of a core 32 so as to shut off communication between theintermediate communication passage 29 and the first communicationpassage 11. The shut-off valve portion 21 a and the end portion 32 c ofthe core 32 form a shut-off valve 27 a. The shut-off valve portion 21 aand the main valve portion 21 c of the valve element 20 perform openingand closing actions in the opposite directions to each other. Asituation where the shut-off valve portion 21 a and the end portion 32 cof the core 32 are brought from a contact state into a separate statewill be indicated as the shut-off valve 27 a is opened or the shut-offvalve portion 21 a is opened. A situation where the shut-off valveportion 21 a and the end portion 32 c of the core 32 are brought from aseparate state into a contact state will be indicated as the shut-offvalve 27 a is closed or the shut-off valve portion 21 a is closed.

Next, the adapter 23 forming the valve element 20 will be described. Theadapter 23 is mainly formed by a large diameter portion 23 c formed tohave a large diameter by a cylindrical hollow member, and a tube portion23 e formed to have a diameter smaller than the large diameter portion23 c. The tube portion 23 e is fitted to an opening end portion on themain valve portion 21 c side of the main valve element 21 so that thevalve element 20 is formed. Thereby, the intermediate communicationpassage 29 passing through in the axial direction is formed in theinside of the main valve element 21 and the adapter 23, that is, theinside of the valve element 20.

The adapter 23 includes a spacer 25 (restrictor portion according to thepresent invention). The spacer 25 is a cylindrical member and has agroove shaped communication passage 25 a passing through the spacer 25in the radial direction at an end of the spacer. An opening area of thecommunication passage 25 a is the smallest in the intermediatecommunication passage 29. In a state where an end portion of the spacer25 on the communication passage 25 a side is in contact with an endsurface 26 b of the pressing portion 26, a predetermined clearance isformed between the adapter 23 and the pressing portion 26. The openingarea of the communication passage 25 a is smaller than an area of theclearance between the adapter 23 and the pressing portion 26. Thus, byadjusting the opening area of the communication passage 25 a serving asa bottleneck of the intermediate communication passage 29, it ispossible to adjust the minimum amount of the coolant flowing through theintermediate communication passage 29. The spacer 25 and the pressingportion 26 form a restrictor mechanism 27 c that adjusts an openingdegree of the intermediate communication passage 29. The restrictormechanism 27 c is a variable restrictor mechanism in which thecommunication passage 25 a has the minimum opening area and an openingarea is changed in accordance with the area of the clearance between thespacer 25 and the pressing portion 26. The spacer 25 may be integratedwith the adapter 23 or the spacer 25 may be fitted and fixed to theadapter 23.

Next, the solenoid 30 will be described. The solenoid 30 mainly includesthe rod 36, a plunger case 38, an electromagnetic coil 31, the core 32formed by a center post 32 a and a base member 32 b, a plunger 35, aplate 34, and a solenoid case 33. The rod 36 is driven in accordancewith electric currents supplied from the outside. The plunger case 38 isa bottomed cylindrical hollow member whose one side is open. The plunger35 is arranged movably in the axial direction with respect to theplunger case 38 between the plunger case 38 and the center post 32 aarranged inside the plunger case 38. The core 32 is fitted to the valvemain body 10 and arranged between the plunger 35 and the valve main body10.

An opening end portion of the plunger case 38 is fixed to an innerperipheral portion of the base member 32 b of the core 32 in a sealedstate, and the solenoid case 33 is fixed to an outer peripheral portionof the base member 32 b in a sealed state. The electromagnetic coil 31is arranged in a space surrounded by the plunger case 38, the basemember 32 b of the core 32, and the solenoid case 33 and not broughtinto contact with a coolant. Thus, it is possible to prevent a decreasein insulation resistance.

The rod 36 is an axial member arranged in a state where the rod has aclearance from a through hole 32 e of the center post 32 a of the core32 so as to be relatively moved with respect to the core 32. One endportion 36 e of the rod 36 is fixed to the plunger 35, and the pressingportion 26 is fitted and fixed to the other end portion 36 h of the rod36.

The pressing portion 26 forming part of the rod 36 will be described.The pressing portion 26 is a disc plate shaped member in which a baseportion 26 a is formed and brim portions are formed from the baseportion 26 a on both sides in the axial direction. One brim portion 26 copposes the large diameter portion 23 c of the adapter 23 in a statewhere the brim portion has a predetermined clearance, and the other brimportion 26 d presses the flange portion 24 d of the pressure-sensitivebody 24 so as to extend and contract the pressure-sensitive body 24. Adistribution hole 26 f through which the coolant is distributed isformed in the base portion 26 a of the pressing portion 26. The pressingportion 26 may be integrated with the rod 36 or the pressing portion 26may be fitted and fixed to the rod 36 and integrally formed.

Between the core 32 and the plunger 35, a spring 37 (second biasingmember according to the present invention) that biases the plunger 35 inthe direction in which the plunger is separated from the core 32 isarranged.

The spring 37 is arranged between the plunger 35 and the core 32.Specifically, one end of the spring 37 is in contact with an end portionof the center post 32 a, the other end is in contact with an end portionof the plunger 35, and the core 32 and the plunger 35 are biased in thedirection in which the core and the plunger are separated from eachother.

Next, a spring 43 (first biasing member according to the presentinvention) that biases the valve element 20 in the valve closingdirection of the main valve portion 21 c will be described. The spring43 formed in a circular truncated cone is arranged between the solenoid30 and the valve element 20. Specifically, one end of the spring 43 isin contact with a stepped portion 36 f of the rod 36 formed at thesubstantially same position as the end portion 32 c of the core 32, andthe other end is in contact with an inside stepped portion 21 h formedon the intermediate communication passage 29 side of the main valveelement 21. The spring 43 is assembled between the main valve element 21and the rod 36 in a state where the spring is compressed by apredetermined amount from natural length, that is, in a state where thespring has an initial set load. Thereby, the spring 43 is not deformedwith drive force of the solenoid 30 being not more than the initial setload, and the valve element 20 and the rod 36 are integrally moved in astate where relative positions are maintained. The spring 43 is deformedupon exceeding the initial set load, and the rod 36 is relatively movedwith respect to the valve element 20. The initial set load of the spring43 is set to be larger than the drive force of the solenoid 30 at thetime of controlling the capacity control valve 1.

Actions of the capacity control valve 1 having the configurationdescribed above will be described. A flow passage running from the thirdcommunication passage 13 to the first communication passage 11 throughthe intermediate communication passage 29 will be called as the “Pc-Psflow passage” below. A flow passage running from the secondcommunication passage 12 to the third communication passage 13 throughthe valve hole 17 will be called as the “Pd-Pc flow passage” below.

First, movement of the rod 36 and movement of the valve portions of thevalve element 20 will be described. First of all, based on FIGS. 1 and2, the movement of the rod 36 and the movement of the valve portions ofthe valve element 20 in a non-energized state of the solenoid 30 will bedescribed. In a non-energized state, the plunger 35 is pushed upward bybiasing force of the pressure-sensitive body 24 and biasing force of thespring 37 (FIG. 1), the main valve portion 21 c of the valve element 20is fully opened, and the shut-off valve portion 21 a is fully closed.The restrictor mechanism 27 c is brought into the minimum restrictionstate by the communication passage 25 a of the spacer 25.

Next, based on FIG. 3, the movement of the rod 36 and the movement ofthe valve portions of the valve element 20 in a state where energizationof the solenoid 30 is started from a non-energized state and the mainvalve 27 b is opened will be described. Since the initial set load ofthe spring 43 is set to be larger than the drive force of the solenoid30 at the time of controlling the capacity control valve 1, in a statewhere the main valve 27 b is opened, the spring 43 is not deformed andthe rod 36 and the valve element 20 are integrally moved. First, whenenergization of the solenoid 30 is started from a non-energized state,the valve element 20 and the rod 36 are integrally and gradually drivenin the forward direction (direction in which the rod 36 pops out fromthe end portion 32 c of the core 32 to the outside). Thereby, theshut-off valve portion 21 a is separated from the end portion 32 c ofthe core 32, the shut-off valve 27 a is opened from a fully closedstate, and the main valve 27 b is gradually narrowed down from a fullyopened state. At the time of controlling the capacity control valve 1,the valve element 20 and the rod 36 are integrally displaced. Thus, thecapacity control valve 1 can stably control an opening degree of themain valve 27 b.

Further, when the rod 36 is driven in the forward direction, as shown inFIG. 4, the shut-off valve 27 a is brought into a fully opened state,the main valve portion 21 c is brought into contact with the main valveseat 15 a, the main valve 27 b is brought into a fully closed state, andthe movement of the valve element 20 is stopped. When the solenoid 30 isfurther driven in a state where the valve element 20 is stopped, thedrive force of the solenoid 30 exceeds the initial set load of thespring 43, the spring 43 is deformed, and relative movement of the rod36 with respect to the valve element 20 is started. Thus, the pressingportion 26 of the rod 36 is separated from the spacer 25 and an openingdegree of the restrictor mechanism 27 c is increased. When the rod 36 isfurther driven, the spring 43 is deformed, the brim portion 26 d of thepressing portion 26 presses the flange portion 24 d of thepressure-sensitive body 24, and the pressure-sensitive body 24 iscontracted, so that it is possible to bring the restrictor mechanism 27c into a fully opened state. When the pressure-sensitive body 24 iscontracted by a predetermined amount, a projected portion 24 h of theflange portion 24 d and a projected portion (not shown) provided in thepartition adjusting portion 24 f are brought into contact with eachother, deformation of the pressure-sensitive body 24 is stopped, and themovement of the rod 36 is also stopped.

The movement of the rod 36 and the movement of the valve portions of thevalve element 20 are described above. Next, actions of the capacitycontrol valve 1 and the variable capacity compressor will be describedbased on FIG. 3. First, a control state of the capacity control valve 1will be described. The control state is a state where the opening degreeof the main valve 27 b is set to an opening degree determined inadvance, and the pressure of the suction chamber of the variablecapacity compressor is controlled to be a set value Pset. In this state,the suction pressure Ps of the suction chamber of the variable capacitycompressor passes through the intermediate communication passage 29,flows to an internal space surrounded by the pressing portion 26 of therod 36 and the flange portion 24 d of the pressure-sensitive body 24,and acts on the pressure-sensitive body 24. As a result, the main valveportion 21 c is stopped at a position where force in the valve openingdirection of the spring 37, force by the solenoid 30, and force by thepressure-sensitive body 24 to be extended and contracted in accordancewith the pressure Ps of the suction chamber are balanced, and thepressure of the suction chamber of the variable capacity compressor iscontrolled to be the set value Pset. However, there is sometimes a casewhere the pressure Ps of the suction chamber is varied with respect tothe set value Pset. For example, when the pressure Ps of the suctionchamber is increased to be more than the set value Pset due todisturbance, etc., the pressure-sensitive body 24 is contracted and theopening degree of the main valve 27 b is decreased. Thereby, since thePd-Pc flow passage is narrowed down, a coolant amount of the dischargepressure Pd flowing in from the discharge chamber to the crank chamberis reduced and pressure of the crank chamber is lowered. As a result, atilting angle of a swash plate of the compressor is increased, adischarge capacity of the compressor is increased, and dischargepressure is lowered. On the contrary, when the pressure Ps of thesuction chamber is decreased to be lower than the set value Pset, thepressure-sensitive body 24 is extended and the opening degree of themain valve 27 b is increased. Thereby, since the Pd-Pc flow passage isincreased, the coolant amount of the discharge pressure Pd flowing infrom the discharge chamber to the crank chamber is increased and thepressure of the crank chamber is increased. As a result, the tiltingangle of the swash plate of the compressor is decreased, the dischargecapacity of the compressor is reduced, and the discharge pressure isincreased. In this way, by the capacity control valve 1, it is possibleto control the pressure of the suction chamber of the variable capacitycompressor to be the set value Pset.

However, even when the opening degree of the main valve 27 b iscontrolled as described above, the pressure of the control chamber(crank chamber) of the variable capacity compressor is graduallyincreased by a blow-by gas flowing through a tiny clearance between apiston and a cylinder bore, and there is sometimes a case where the setpressure and the set discharge amount cannot be stably maintained.Therefore, as shown in FIG. 4, by letting the coolant of the controlchamber pass through the communication passage 25 a of the spacer 25from the third communication passage 13 and flow to the firstcommunication passage and the suction chamber via the intermediatecommunication passage 29, it is possible to stabilize the pressure ofthe control chamber (crank chamber) of the variable capacity compressor,and hence it is possible to improve stability of the capacity controlvalve 1.

Next, a liquid coolant discharge state of the capacity control valve 1will be described based on FIG. 4. After the compressor is stopped for along time, a liquid coolant (made by cooling and liquefying a coolantduring abandonment) is accumulated in the crank chamber. Thus, in orderto ensure predetermined discharge pressure and a predetermined dischargeflow rate after start-up of the compressor, there is a need fordischarging the liquid coolant as soon as possible. At the time ofliquid coolant discharge, pressure of the third valve chamber 16communicating with the crank chamber and the suction pressure Ps arehigh pressure, the pressure-sensitive body 24 is contracted, thesolenoid 30 is driven in the forward direction, the pressure-sensitivebody 24 is pressed by the pressing portion 26 of the rod 36, and therestrictor mechanism 27 c is forcibly brought into a fully opened state.Thereby, the opening degree of the restrictor mechanism 27 c is notchanged from start of the liquid coolant discharge to completion of theliquid coolant discharge, and it is possible to discharge the liquidcoolant from the crank chamber to the suction chamber via the Pc-Ps flowpassage for a short time.

In this way, by the restrictor mechanism 27 c, the control chamber andthe suction chamber of the variable capacity compressor communicate witheach other via the restrictor mechanism 27 c and the intermediatecommunication passage 29. Thus, it is possible to suppress the pressureof the control chamber from being increased by the blow-by gas so as tostabilize the pressure of the control chamber. Thus, it is possible toimprove control stability of the capacity control valve 1. At the timeof the liquid coolant discharge of the capacity control valve 1, the rod36 is relatively moved with respect to the valve element 20, and it ispossible to forcibly separate the pressing portion 26 of the rod 36 fromthe spacer 25 of the restrictor mechanism 27 c. Thereby, at the time ofthe liquid coolant discharge, it is possible to maintain the openingdegree of the restrictor mechanism 27 c in a fully opened stateirrespective of the pressure of the third valve chamber 16 communicatingwith the crank chamber and the suction pressure Ps. Thus, it is possibleto discharge the liquid coolant from the crank chamber to the suctionchamber via the Pc-Ps flow passage for a short time.

The embodiment of the present invention is described with the drawingsabove. Specific configurations are not limited to the embodiment but thepresent invention also includes changes and additions within the rangenot departing from the gist of the present invention.

In the above embodiment, the first pressure of the first valve chamber14 is the suction pressure Ps of the variable capacity compressor, thesecond pressure of the second valve chamber 15 is the discharge pressurePd of the variable capacity compressor, and the third pressure of thethird valve chamber 16 is the pressure Pc of the crank chamber of thevariable capacity compressor. However, the present invention is notlimited to this but with the first pressure of the first valve chamber14 being the pressure Pc of the crank chamber of the variable capacitycompressor, the second pressure of the second valve chamber 15 being thedischarge pressure Pd of the variable capacity compressor, and the thirdpressure of the third valve chamber 16 being the suction pressure Ps ofthe variable capacity compressor, it is possible to respond to variousvariable capacity compressors.

REFERENCE SIGNS LIST

-   -   1 capacity control valve    -   10 valve main body    -   11 first communication passage    -   12 second communication passage    -   13 third communication passage    -   14 first valve chamber    -   15 second valve chamber    -   15 a main valve seat    -   16 third valve chamber    -   17 valve hole    -   20 valve element    -   21 main valve element    -   21 a shut-off valve portion    -   21 c main valve portion    -   23 adaptor    -   24 pressure-sensitive body    -   24 a bellows    -   24 d flange portion    -   25 spacer (restrictor portion)    -   25 a communication passage    -   26 pressing portion    -   26 c brim portion    -   26 d brim portion    -   27 a shut-off valve    -   27 b main valve    -   27 c restrictor mechanism    -   29 intermediate communication passage    -   30 solenoid portion    -   31 electromagnetic coil    -   32 core    -   35 plunger    -   36 rod    -   37 spring (second biasing member)    -   43 spring (first biasing member)    -   Fsol magnetic attracting force    -   Ps suction pressure (first pressure) (third pressure)    -   Pd discharge pressure    -   Pc control chamber pressure (third pressure) (first pressure)    -   Pset suction pressure set value

The invention claimed is:
 1. A capacity control valve that controls a flow rate or pressure of a variable capacity compressor in accordance with a valve opening degree of a valve portion, the capacity control valve being characterized by comprising: a valve main body having a first communication passage through which a fluid of first pressure passes, a second communication passage arranged adjacent to the first communication passage, the second communication passage through which a fluid of second pressure passes, a third communication passage through which a fluid of third pressure passes, and a main valve seat arranged in a valve hole which provides communication between the second communication passage and the third communication passage, wherein the first pressure is suction pressure of the variable capacity compressor, the second pressure is discharge pressure of the variable capacity compressor, and the third pressure is a pressure of a crank chamber of the variable capacity compressor; a pressure-sensitive body arranged in the valve main body on the third communication passage side, wherein the pressure-sensitive body has a bellows and a flange at one end of the bellows, another end of the bellows is fixed to a partition that defines a valve chamber with the valve main body, and the pressure sensitive body expands and contracts according to the suction pressure which is transmitted to the pressure-sensitive body via an intermediate communication passage providing communication between the first communication passage and the third communication passage; a solenoid that drives a rod having a pressing portion that presses the pressure-sensitive body, wherein the pressing portion has a brim portion on a first side in an axial direction facing the flange of the pressure-sensitive body and an end surface on a second side opposite to the first side in the axial direction; a valve element having a first portion of the intermediate communication passage, a main valve portion to be separated from and connected to the main valve seat so as to open and close the valve hole, and a restrictor portion having a second portion of the intermediate communication passage; the restrictor portion opposing the pressing portion and having a minimum communication passage penetrating through a wall of the restrictor portion, wherein an opening area of the minimum communication passage is a smallest opening area in the intermediate communication passage; and a first spring that biases the valve element in the valve closing direction of the main valve portion, wherein the brim portion of the pressing portion presses on the flange of the pressure sensitive body, and the pressing portion and the restrictor portion constitute a restrictor mechanism; wherein the restrictor mechanism adjusts an opening degree of the intermediate communication passage between the end surface of the pressing portion and the restrictor portion, wherein the restrictor mechanism is a variable restrictor mechanism in which the opening degree of the intermediate communication passage is changed in accordance with an area of a clearance between the restrictor portion having the minimum communication passage and the end surface of the pressing portion, and the rod is relatively moved with respect to the valve element so as to control an amount of separation between the pressing portion and the restrictor portion of the restrictor mechanism.
 2. The capacity control valve according to claim 1, characterized in that the solenoid further includes a plunger connected to the rod, a core arranged between the plunger and the valve main body, an electromagnetic coil, and a second spring arranged between the plunger and the core.
 3. The capacity control valve according to claim 1, characterized in that the first spring is arranged between the rod and the valve element.
 4. The capacity control valve according to claim 3, characterized in that the solenoid further includes a plunger connected to the rod, a core arranged between the plunger and the valve main body, an electromagnetic coil, and a second spring arranged between the plunger and the core. 